Exterior Durability in All-Acrylic Architectural Gloss Coatings: Gloss Retention and Dirt-Pickup Resistance

By Robert W. Sandoval, Tyler J. Bell, Mary Jane Hibben, Mike Wildman

The primary function of exterior architectural coatings is to protect a substrate and withstand exposure to weather. With a wide variety of weather conditions in the United States, a coating must withstand many harsh conditions, including freeze/thaw, rain, ultraviolet (UV) exposure, wind, smog, and ice/hail.

Many methods have been developed to test for the variety of conditions that an exterior coating may experience. Accelerated laboratory tests are popular due to the shorter time that it takes to run these tests. However, the “gold standard” for many coating manufacturers is to expose the coating outside in regions with extreme weather conditions. Typically, multiple years of exterior exposure are desired for new products, which is not always feasible during product development.

Dirt-pickup resistance (DPUR) is typically defined as the ability of a coating to resist dirt, which over the course of time, darkens the film.